1. Field of the Invention
The present invention is directed to a quick mounting of and a quick release of a tool from a magnetic chuck, tool mounting assembly using a combined magnetic and mechanical coupling.
2. Description of the Prior Art
Heretofore, several tool mounting assemblies for mounting a working tool at the end of a power drill or hand drill where magnets are used to hold the tool to a tool holder have been proposed. Examples of such previously proposed assemblies for magnetically mounting a tool to a power drill or hand drill are disclosed in the following U.S. Patents:
______________________________________ U.S. Pat. No. Patentee ______________________________________ 3,970,407 Uffman 4,514,117 Scott 5,577,426 Eggert et al 5,603,248 Eggert et al ______________________________________
The Uffman, U.S. Pat. No. 3,970,407 teaches a rotary cutter. The rotary cutter includes a holder assembly including a cup shaped body that has a stem extending from the bottom of the cup for being mounted in a chuck of a power tool. Inside the cup shaped portion is a generally cylindrical, magnet slug which has a diametrical slot extending across the outer facing end of the slug and which is held inside the cup shaped portion by a screw which extends through a bottom of the slot upwardly through the slug and into the stem. Then, a circular cutter has a reduced-in-diameter collar that fits within the hollow defined by the cup shaped body and bares against the exposed surface of the magnetic slug and is held to the slug by the magnetic attraction between the rotary cutter and the slug. Also, the inner end of the reduced-in-diameter collar of the circular cutter has two (2) diametrically opposed projections which are received in the slot so that a turning force of torque can be applied to the rotary cutter by reason of the engagement between the projections and the slot.
The Scott U.S. Pat. No. 4,514,117 teaches a quick-change tool holder and tool. The tool holder is generally cylinder in shape and includes a threaded bore at the rear end thereof for being threaded onto an adapter shaft which is adapted to be received into and held in a chuck. A tool, such as a drill has a tapered or conically shaped base and the cylindrical tool holder has a conical shaped outer opening for receiving the base of the tool. Between the tapered shank or base of the tool and the conically shaped opening there is provided a keyway in the form of an axially extending slot in the wall of the conically shaped opening which is aligned with an axially extending snot in the outer wall surface of the tapered base of the tool for receiving a magnet key. The magnet function of the key retains the ferromagnetic tapered shank within the tapered bore portion in the tool holder and facilitates easy removal of the drill bit tool from the tool holder.
The Eggert et al U.S. Pat. Nos. 5,577,426 and 5,603,248 disclose a hand held tool with a magnetic bit holder. As shown in FIG. 2 of this patent, a hex cross section base of a tool, such as a Phillips head screw driver is received within bore having a hex configuration. At the bottom of the bore there is positioned a permanent magnet which is held in the bottom of the bore by retainer plate. The tool holder includes a stem that extends to a handle for manual manipulation, e.g., rotation, of the tool mounted in the tool holder.